Carburetor



Sept. 1l, 1934. l.. DURR GARBURETOR Filed Aug. 1s, 1929 l cu MII., 1

fnrenor Patented Sept. 11, 1934 UNITED STATES CARBURETOR Ludwig Drr,

Friedrichshafen, Germany, assigner to Luftschiibau Zeppelin GesellschaftMit Beschrankter Haftung, Friedrichshafen, Germany Application August13, 1929, Serial No. 385,633

y In Germany September 13, 1928 2 claims.

My invention relates to internal combustion engines and has specialreference to engines of this kind which are fed with gaseous fuel. Itconsists in a novel safety device.

The main object of the invention is to shut off the gas supplyautomatically when stopping the engine.

Another object is to have a device for this purpose which is highlyreliable and also simple in construction and which cannot be brought outof order by external influences.

The drawing represents an example embodying my invention.

' Fig. 1 is an elevation, partly in section, of an arrangement of a gasflue and a mixing chamber in combination with a carburetor attached to agas engine.

In Fig. 2 the main portion of Fig. 1 is reproduced on a larger scale.

The example is a special one in which the motor 20 can be supplied withliquid fuel, such as gasoline or the like, by means of a carburetornozzle 3, or it can be fed by gaseous fuel entering through tube 2. Theway of the gaseous fuel is indicated by arrows G, whereas arrow L pointsout the way in which the liquid fuel flows. Both kinds of fuels can beturned off by means of valves or cocks 5 and 25, respectively. The airto be mixed with the gaseous fuel or to flow through the carburetor 3for Carburation with liquid fuel enters the system in the direction ofarrow A and flows through a mixing chamber 4 in which it mixes with thegaseous fuel, if this is turned on.

My automatic valve 1 is situation within tube 2 which is provided with avalve seat ll'adapted for receiving valve 1. The stem 8 of valve 1 isguided in a sleeve-like portion of the small casing 9. Springs 15 withone end fastened to this casing, their other ends being fastened tovalve 1, tend to hold the valve shut. The outer end of stem 8 isconnected to a membrane or diaphragm 12 which may be made from metal orleather or other suitable material. This membrane is held at itscircumference by means of a ring 17 and bolts or screws 18. Casing 9together with membrane 12 confine space 13. A cover 16 encloses a secondspace 19 situated on the other side of membrane 12, This space 19 may ormay not be connected to the open air, as circumstances may afford. Space13 by means of bore 24 and of tube 14 is connected to the intake 7 ofmotor 20. Tube 14 opens into intake 7 at a point situated betweenthrottle valve 21 and the motor 20, preferably close to the motorcylinders.

The operation of the device is as follows:

When the engine is run with gaseous fuel and consequently when the maingas valve 5 is turned on, starting of the motor effects avacuum in theintake 7. This vacuum is imparted to space 13 through tube 14 and itcauses membrane 12 which is in the position represented in Fig. 1 toswing to its right hand position, as shown in Fig. 2. This movement ofthe membrane causes the valve 1 to open. As soon as the motor stopsagain the sucking effect at 7 and consequently in tube 14 vanishes andmembrane 12 returns to its original position shown in Fig. 1 therebyclosing valve 1.

This construction is of special importance with an arrangement asrepresented in Fig. 1, in which the engine can be fed with gaseous fuelor with liquid fuel, alternately. But it will also be of advantage withmotors being supplied with gaseous fuel only.

The main thing is that the connection between the storage of the fuelgas and the motor is shut off automatically as soon as the motor stops.The device according to my invention has the great advantage of4extra-ordinary reliable operation, because the working of the membraneis directly dependant on the vacuum in the intake by means of narrowtube 14 and special small space 13. Consequently, when making use of mydevice there will be absolute safety against fuel gas escaping into theopen air.

I do not want to be limited to the details described or shown in thedrawing as many variations will occur to those skilled in the art.

What I claim is:

1. 4In a fuel feeding device for an internal combustion engine, incombination, a conduit leading to the intake of said engine, means fordirecting liquid fuel into said conduit, means for directing air intosaid conduit, means for directing gaseous fuel into said conduit, avalve controlling the passage of said gaseous fuel into said conduit, astem connected to said valve, a diaphragm connected to said stem at apoint spaced from the valve, means defining a chamber with the diaphragmforming a portion of the chamber wall, a second conduit connectedbetween said chamber and the engine intake whereby a vacuum is createdin said chamber when the engine is running which will cause a pressuredifferential on the two sides of the diaphragm to thereby move, thediaphragm and the valve stem and hold the valve open, and spring meansfor closing and holding the valve closed when the vacuum is ineffective.

2. The combination recited in claim 1 wherein further the side of thediaphragm away from the chamber is surrounded by an enclosure whichmaintains a uniform pressure on the said side of the diaphragm andprevents any interference on the diaphragm.

LUDWIG DRR.

